The Invention relates to the field of ignition system diagnostics.
In particular, the Invention, in one embodiment, is an adapter that enables the continued use of existing oscilloscopes to test secondary ignition patterns with the new style coil on ignition systems adopted by the majority of automobile manufactures.
The Invention has particular application (but is not thereby limited) in the field of automotive mechanics and diagnostics, where it is useful to use existing automotive diagnostic equipment, such as multi-strike capable oscilloscopes, to test secondary ignition patterns on coil on plug ignition systems, and to be capable of viewing multi cylinder waveforms on the read-out screen at the same time.
For the past many years automobile gasoline engines have been diagnosed using an automotive oscilloscope attached to the ignition system. This produces a waveform on a screen that provides valuable information on the internal condition of some components of the engine and of its ability to run at peak efficiency, that the spark generated by the ignition coil has been distributed to the proper spark plug and related wiring at the correct the time via a device called the distributor. It is a mechanical device that operates at a revolutionary speed of one half that of the crankshaft and is an integral part of the engine. The spark voltage in common practice is negative (xe2x88x92) in relation to engine ground.
With modern computer technology the distributor has been deleted from the engine and spark has been controlled with an on board computer controlling multiple ignition coils instead of just one in the case of a distributor equipped engine. A six cylinder engine would be equipped with three ignition coils capable of sparking at both positive (+) and negative (xe2x88x92) voltages. A new technology was developed to allow automotive oscilloscopes to test this type of ignition system. By having one inductive pickup attached to each spark plug wire (instead of just one on a distributor equipped model that would attach between the coil and distributor) the oscilloscope could read this data and display it on the screen after inverting the positive signals to be displayed properly.
Starting around 1997 many vehicle manufacturers started using a new technology that had one ignition coil per spark plug and in some cases it would sit directly on top of the spark plug with no external wiring to allow an inductive pickup to be attached. With this new system all coils produce a negative (xe2x88x92) spark. The vehicle manufacturing community decided that all diagnostics on this system could be done with the onboard computer and proper interface tool, eliminating the need for an automotive oscilloscope. The engine diagnostic equipment manufacturing community, perhaps seeing a chance to sell expensive on board computer interface diagnostic tools, have not pursued creating an adapter for their existing equipment. The fact remains that many automotive shops and technicians have purchased expensive equipment to work on the older vehicles and many automotive technicians have spent years refining their ability to read ignition waveforms and feel that a valuable part of their diagnostic routine has been taken away from them.
It is well-known in the art to use an apparatus or method to determine and display information relating to ignition systems diagnostics. See for example CDN Patent No. 1,050,110, which is comprised of an automotive analyzer apparatus with oscilloscope and probe means, and U.S. Pat. No. 5,296,869, a digital engine analyzer with oscilloscope display and microprocessor. Also see CDN Patent No. 2,321,510, which describes an apparatus and method for detecting electric ignition signals for a coil on plug of an internal combustion engine, and CDN Patent No. 2,133,689, an apparatus and method for engine diagnosis using waveform analysis.
Testing of distributorless ignition systems has also been known for some time. See U.S. Pat. No. 5,641,898, which discloses an ignition module tester with electrical input terminals and CDN Patent No. 2,148,057, a distributorless ignition test device comprised of an adapter with inport port coupled to an electrical ground.
It is also known to use adapters in the field of ignition diagnostics. See U.S. Pat. No. 5,132,625, which is comprised of ignition spark sensing and detection means with manual voltage amplitude variation for a method and means for a distributorless ignition adapter for diagnostic oscilloscopes.
It is an object of the Invention to overcome limitations in the prior art of vehicle ignition diagnostic equipment and methods. The existing prior art inadequately addresses the need for an affordable and useful interface between widely used diagnostic equipment and the recently developed computerized vehicle ignition systems. None of the prior art discloses a practical invention that utilizes a method or means to accommodate interaction between oscilloscopes and coil ignition systems.
According to the teachings of the present invention there is provided a distributorless ignition adapter for diagnostic oscilloscopes which includes an interface box, an oscilloscope connection cord and several inductive pick ups. The oscilloscope connection cord has a first end connected to the interface box and a second end terminating in an oscilloscope plug. The several inductive pick ups are connected to the interface box, whereby passage of electrical current through ignition coils is sensed and data relating to properties of the electrical current is transmitted to an oscilloscope via the interface box and the oscilloscope connection cord.
The Invention relates to an adapter device that enables interaction between engine coil ignition systems and oscilloscopes. The Invention has particular application (but is not thereby limited) in the field of automotive ignition system diagnostics, where it is particularly beneficial to automotive technicians to have the ability to use previously purchased and adopted diagnostic equipment, with the in-line coil ignition systems, recently developed by vehicle manufacturers.
Although beneficial results may be obtained through the use of the distributorless ignition adapter for diagnostic oscilloscopes, as described above, even more beneficial results may be obtained when each of the several inductive pick ups is sufficiently flexible to wrap around an ignition coil. This enables the inductive pick ups to be adapted to different sizes of ignition coil.
Although beneficial results may be obtained through the use of the distributorless ignition adapter for diagnostic oscilloscopes, as described above, even more beneficial results may be obtained when each of the several inductive pick ups is detachably secured to the interface box. This enables a service technician to alter the number of inductive pick ups to correspond with the number of ignition coils for a particular model of engine. One way of detachably securing the inductive pick ups to the interface box is to provide the interface box with a plurality of receiving jacks. Each of the several inductive pick ups can be provided with a lead wire terminating in a pick up plug which is adapted to mate with one of the plurality of receiving jacks.
The Invention was designed to permit interaction between vehicles such as Ford vehicles with coil on plug ignition systems and the majority of 12V negative firing ignition systems that permit inductive pickup connection to the outer case of the ignition coil(s), with oscilloscopes with distributorless ignition system connectors or standard ignition secondary pickups. The Invention enables the reading for each ignition coil to be displayed on a suitable oscilloscope read out screen at the same time, such that a ten cylinder engine with ten ignition coils, would simultaneously have ten cylinder waveforms displayed on the oscilloscope read out screen. As the inductive pickups on the Invention are removable, it permits an oscilloscope to be used with engines that are not normally capable of being diagnosed in this manner, such as motorcycles and other small engines. Also, the use of flexible pickups allows for variations in coil size from different manufacturers and reduces the need for multiple sets of leads. A yellow colour was chosen for the colour of several components of the Invention as it is the colour normally associated with secondary ignition testing and it makes the components much more visible for easier installation on the ignition system being tested, there also being a safety factor in making things highly visible (although yellow is not claimed as a necessary or essential feature).
These and other objects and advantages of the Invention are apparent in the following description of the preferred embodiment of the Invention, which is not intended to limit in any way the scope or the claims of the Invention.
The preferred embodiment of the Invention displays a preferred composition but is not intended to limit the scope of the Invention. It will be obvious to those skilled in the art that variations and modifications may be made without departing from the scope and essential elements of the Invention.
The preferred embodiment of the Invention is a coil ignition oscilloscope adapter device comprised of interface box 1, receiving jacks 2, pickup plugs 3, lead wires 4 flexible inductive pickups 5, connection cord 6 and oscilloscope plug 7.